Conventionally, a method of forming a film on the surface of metal, the film being made of other metal materials or ceramics, is widely used to provide wear resistance to the surface of the metal. Such a metal on which a film has been formed is usually used in a temperature environment from room temperature to about 200° C., and in most of the cases, oil lubricant is also applied on the surface. However, an oil lubricant cannot be used when such a metal is used to make components, such as aero-engine components, that are used in environments with a wide temperature range from room temperature to about 1000° C. Therefore, it becomes necessary to exhibit wear resistance properties by using the strength or lubricant capability of the material itself.
Wear-resistant material that can be used for components that are used in high temperature environment, such as aero-engine components or the like, include metal material such as Tribaloy and Stellite with cobalt (Co) and molybdenum (Mo) as a main component. Conventionally, methods of forming a film made of these metal materials on a material to be treated using cladding by welding or using plasma spraying are used. However, these methods of forming the film have a problem such that the material to be treated is thermally deformed or a film with satisfactory adhesion strength is not obtained.
Technologies have been disclosed for forming a film that does not cause thermal deformation of the material to be treated or reduction in the strength thereof but that has sufficient wear resistance even under high temperature. For example, technologies have been disclosed for forming a film based on an electrode material by generating pulsed discharge between a powder compact and a material to be treated (e.g., see Patent document 1 or Patent document 2). Each of Patent document 1 and Patent document 2 disclose a method of mixing an oxide into an electrode as a method of solving the problem on wear resistance in an intermediate temperature range, which is the problem on the conventional film.
Furthermore, technologies have been disclosed for providing an electrode used for electrical-discharge surface treatment, which is obtained by pulverizing powder without being oxidized in a manufacturing process, for an electrical-discharge surface treatment electrode (e.g., Patent Document 3). Patent document 3 discloses a method of forming a green compact electrode by using powder obtained by pulverizing metal powder in a solution, mixing wax as a binder in a mixture containing the pulverized metal powder and the solution, and drying and granulating the mixture in an inert gas atmosphere.
Patent document 1: International Publication No. 2004/029329 Pamphlet
Patent document 2: International Publication No. 2005/068670 Pamphlet
Patent document 3: Japanese Patent Application Laid-Open No. 2005-213560
Patent document 4: International Publication No. 2004/011696 Pamphlet